The present invention relates to a magnetic recording mode for improving surface recording density greatly and particularly to magnetic recording media, magnetic heads and a magnetic read-write apparatus using the same for achieving high-density magnetic recording.
Recently, improvement of recording density in the field of magnetic recording, particularly in magnetic recording disks, is remarkable and researches and developments are being hastened to achieve a higher-density read-write apparatus. The recording mode used in magnetic recording disks at present is a longitudinal magnetic recording mode in which recorded magnetization is directed to a track. In order to improve the recording density more greatly, a perpendicular magnetic recording mode free from self-demagnetization even in high linear recording density has been proposed or researched eagerly to be used in magnetic recording media (Iwasaki and Ouchi: IEEE Trans. Magn., MAG-14, 849 (1978), and so on) but the mode has been not yet put into practical use.
On the other hand, an obliquely magnetic recording mode free from self-demagnetization even in high linear recording density as well as the perpendicular magnetic recording mode is used in the field of VTRs in which longitudinal magnetic recording is mainly carried out. Particularly, as for a recording medium, an obliquely deposited Co--Ni tape has been put into practical use as a high-band 8 mm VTR magnetic tape, and a tape improved in characteristic is expected to be used also as a small-size digital VTR tape in the future (Yoshida, Shinohara and Odagiri: Journal of The Magnetics Society of Japan, Vol. 18, No. S1,439 (1994)).
In a magnetic recording using a ring type magnetic head used in magnetic recording at prevent, the fact that the obliquely magnetic recording mode is more preferable in high-density recording than the longitudinal magnetic recording mode and the perpendicular magnetic recording mode has been confirmed by the simulation by Tagawa et al in Tohoku University (Tagawa, Shimizu and Nakamura: Journal of The Magnetic Society of Japan, Vol. 15, No. S2,827 (1991)). Also in magnetic recording disks, it is expected that recording density will be improved remarkably by use of the obliquely magnetic recording mode.
In the case of a magnetic tape, a magnetic recording medium having an axis of easy magnetization inclined to the recording direction can be formed by obliquely depositing, for example, a ferromagnetic Co--Ni alloy. In the case of a magnetic disk, it is theoretically possible to form a magnetic recording layer having an axis of easy magnetization inclined circumferentially on a circular substrate as disclosed also in JP-A-58-128023, but it is difficult to mass-produce such magnetic disks as products. Accordingly, to put magnetic recording disk devices using an obliquely magnetic recording mode into practical use has been considered to be almost impossible.